CentOS - Dec 2011 - Putty error "Network error: Software caused connection abort"

Hi every: I have a test or development environment in my Windows
workstation with VMware Workstation 8.0 where I have around 7 VM with
CentOS 6.2 and each of them have 2 network interfaces: one bridge and the
other NAT. Since a few days I have been experimenting some problems with
Putty because I get this error:

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PuTTY Fatal Error
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Network error: Software caused connection abort
---------------------------
OK
---------------------------

I did not touch any SSH configuration so I can't see where the problem is,
any help or solution to this?
Cheers and thanks in advance

Ing. Reynier P?rez Mira
Cel: +58 424.180.5609 / +58 416.921.7406
Correo: reynierpm at gmail.com / reynierpm at hotmail.com